Drill bits of this kind conventionally have a shank which fits inside the drill housing and an exposed head at the forward end. The head is provided with teeth on a drilling face at its working end. The shank has splines which are engaged by corresponding splines in a chuck secured in the drill hammer. The rear end of the bit shank forms a striking face onto which a reciprocating piston hammer impacts during operation. Between the striking face and the splines, is a section of reduced diameter. This section defines a pair of shoulders between which a retaining ring, normally above the chuck, slidably engages the bit. The section of reduced diameter has to be longer than the axial thickness of the retaining ring. This allows for the necessary axial or longitudinal movement of the bit.
The drill hammers operate with different air flow paths which sometimes require the bit to include a foot valve tube. There is however a tendency towards drill hammers with bits that do not require these tubes.
The features required on a bit make this component a difficult one to machine. They also dictate that it must be of a certain minimum length which affects its weight and the overall length of the drill hammer. A drill hammer will ordinarily use about five bits during the course of its life.